Characterization Of Mitochondrial Morphology And Mitochondrial Function In Rat After Acute Spinal Cord Injury

Objective This stduy not only described the pathological changes of spinal cord injury in subcellular organelle level, but also laid the foundation for mitochondrial targeting spinal cord injury.Methods 108 adult SD rats were randomly divided into 6 groups:a sham operation group, SCI 2h group, SCI 4h group, SCI 8h group, SCI 16 h group, SCI 24 h group, n = 18(6 for transmission electron microscopy, 6 for biochemical function analysis, 6 for Western blot analysis).The mitochondrial morphology was observed by TEM. The mitochondrial dynamics was determined though the expression of mitochondrial fusion and fission. Mitochondrial oxidative damage was measured malondialdehyde(MDA), glutathione(GSH) and ATP content. The changes of mitochondrial membrane permeability was detected mitochondrial Na+-K+-ATP enzyme activity and mitochondrial membrane potential(MMP). Apoptosis was measured the release of Cytochrome C and the expression of caspase-3 by using the Western blot.Results Mitochondrial morphology changed following acute spinal cord injury. The protein of mitochondrial fusion-related genes(Mfn1) increased at 2h, 4h, and 8h, and showed a downward trend after 8h. The protein of mitochondrialfission-related genes(Drp1) decreased at 2h and 4h, and increased at 8h,16 h and 24 h and showed a upward trend after 8h. After SCI, the level of MDA was significantly elevated, the level of GSH and ATP were significantly declined, the level of MMP and mitochondrial Na+-K+-ATP enzyme activity were reduced. The release of Cytochrome C and the expression of caspase-3 were increased.Conclusions It was the mitochondrial tendency of fusion that dominated at the early stage after SCI, and in the later fission dominated. Mitochondrial morphology and mitochondrial functions could be gradually damaged, and changed obviously at 4h-8h after SCI.